Defensive structures prevent the formation of avalanches. In other circumstances, when an avalanche is released, it can be diverted or intercepted by a dam. Other means of protection against avalanches include physical structures for buildings and snow sheds. We conduct research and offer advice on structural avalanche protection.
Defensive measures in the path and runout zone of released avalanches are restricted to protecting buildings and other assets. An avalanche can be arrested and brought to a standstill by retention dams and retarding mounds. In order to stop an avalanche completely, depending on its speed, a dam may need to be more than 20 m tall. Deflecting dams divert the snow masses to areas where they cannot cause any destruction. Compared with defensive structures, dams are often less expensive to construct, but they occupy a lot of land and permanently change the landscape. Many dams have a dual function: they protect against avalanches in wintertime, and against flooding and debris flows once the snow has melted.
Snow sheds and protection for buildings
Also known as avalanche galleries or tunnels, snow sheds are the classic structures for protecting transportation routes. Avalanches either overflow the shed or deposit their snow on the roof without adversely affecting the traffic. If they are sufficiently long, snow sheds afford very considerable protection. Protecting buildings ranks among the oldest means of defence against avalanches. It is an efficient method of reducing the risk to which people and property are exposed. Among the typical measures for protecting buildings are wall reinforcement, the erection of a solid structure (Spaltkeil), rather like a log splitting wedge, to break the avalanche, and a building design (Ebenhöch) in which the roof seamlessly merges with the terrain or an embankment.